{"id":"CVE-2023-27491","url":"https://www.cyber-defence.io/tools/cve/CVE-2023-27491","generatedAt":"2026-10-25T14:30:32.834Z","title":"Prior to versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9, There is a possibility that non compliant HTTP/1 service may allow malformed requests, potentially leading to a bypass of security policies.","description":"Envoy is an open source edge and service proxy designed for cloud-native applications. Compliant HTTP/1 service should reject malformed request lines. Prior to versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9, There is a possibility that non compliant HTTP/1 service may allow malformed requests, potentially leading to a bypass of security policies. This issue is fixed in versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9.","published":"2023-04-04T19:15:07.000Z","lastModified":"2026-06-17T05:45:19.000Z","status":"Modified","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":9.1,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"},"cwe":["CWE-20","CWE-444"],"affected":["envoyproxy/envoy"],"epss":{"score":0.00869,"percentile":0.58432,"date":"2026-10-24","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.87%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://datatracker.ietf.org/doc/html/rfc9113#section-8.3","tags":["Not Applicable"],"source":"security-advisories@github.com"},{"url":"https://datatracker.ietf.org/doc/html/rfc9114#section-4.3.1","tags":["Not Applicable"],"source":"security-advisories@github.com"},{"url":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-5jmv-cw9p-f9rp","tags":["Exploit","Vendor Advisory"],"source":"security-advisories@github.com"},{"url":"https://www.rfc-editor.org/rfc/rfc9110#section-5.6.2","tags":["Not Applicable"],"source":"security-advisories@github.com"},{"url":"https://datatracker.ietf.org/doc/html/rfc9113#section-8.3","tags":["Not Applicable"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://datatracker.ietf.org/doc/html/rfc9114#section-4.3.1","tags":["Not Applicable"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-5jmv-cw9p-f9rp","tags":["Exploit","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.rfc-editor.org/rfc/rfc9110#section-5.6.2","tags":["Not Applicable"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2023-27491","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}